On 12/12/2013 07:55 PM, Mel Gorman wrote:
> X86 TLB range flushing uses a balance point to decide if a single global TLB
> flush or multiple single page flushes would perform best. This patch takes
> into
> account how many CPUs must be flushed.
>
> Signed-off-by: Mel Gorman <[email protected]>
> ---
> arch/x86/mm/tlb.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
> index 09b8cb8..0cababa 100644
> --- a/arch/x86/mm/tlb.c
> +++ b/arch/x86/mm/tlb.c
> @@ -217,6 +217,9 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned
> long start,
> act_entries = mm->total_vm > act_entries ? act_entries : mm->total_vm;
> nr_base_pages = (end - start) >> PAGE_SHIFT;
>
> + /* Take the number of CPUs to range flush into account */
> + nr_base_pages *= cpumask_weight(mm_cpumask(mm));
> +
flush range calculation base on per cpu, since no matter how many cpus
in the process, tlb flush and refill time won't change.
> /* tlb_flushall_shift is on balance point, details in commit log */
> if (nr_base_pages > act_entries || has_large_page(mm, start, end)) {
> count_vm_event(NR_TLB_LOCAL_FLUSH_ALL);
>
--
Thanks
Alex
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